Explanation:

- SEBI (Option 1):

Securities and Exchange Board of India (SEBI) is the regulator for the securities and capital markets in India. It oversees and regulates the functioning of stock exchanges, mutual funds, brokers, and other intermediaries.

- RBI (Option 2):

Reserve Bank of India (RBI) is the central bank of India. It regulates the monetary policy and ensures financial stability, primarily focusing on the banking sector and currency management.

- NPCI (Option 3):

National Payments Corporation of India (NPCI) is responsible for creating robust payment and settlement infrastructure, including systems like UPI and RuPay, but it is not a market regulator.

- SBI (Option 4):

State Bank of India (SBI) is a banking and financial services organization. It does not play a role in regulating financial markets.

- NSE (Option 5):

National Stock Exchange (NSE) is a leading stock exchange in India. It functions as a platform for trading securities but isn't a regulator.